The speed of light may not be as constant as is commonly thought

Many things in our life are permanent. A sense of disappointment after the chocolate tile is finished, for example. Unpredictability of 2016. And, of course, the speed of light.

But wait! Maybe it is not so. A new study suggests that the speed of light in a vacuum did not always have the same value as now (299792458 meters per second), but was actually slightly higher at the beginning of the universe's existence - 13.8 billion years ago.

Theory of variable light speed

This theory comes from Professor Juan Mageiju from Imperial College in London. Mageiju first proposed the idea of variable light speed in 1998 and now says he knows a way to test it.

The theory is that immediately after the Big Bang there must have been a way of spreading heat and energy around the universe before gravity could reach any of its corners. At this point, the best theory of scientists about how this happened is known as inflation is a period of rapid growth, the speed of which was much higher than the current rate of expansion of the universe.

What is the "horizon problem"

This helps to solve the so-called "horizon problem", where all parts of the universe today are roughly the same in a broad sense, wherever we look. But if the speed of light was always constant, this theory does not make sense, since the energy could not evenly distribute.

Spectral Index

Mageiju says that the speed of light was higher after the Big Bang, and this allowed the universe to become uniform in the early stages. To test this, we can look for oscillations in a cosmic microwave background - a fossil relic of the early universe known as the spectral index.

Mageiju predicts that this figure should be 0.96478. At the moment, the best estimate stands at around 0.968, given the uncertainties.

"If the observations conducted by scientists in the near future will find this number and confirm its accuracy, this will lead to a change in Einstein's theory of gravity," the scientist said in a statement to the press.

Consequences of the new theory

If he is right, these results will lead to wider consequences for Einstein's theory of relativity, because they assume that the speed of light was not constant, as we always thought. If he is wrong, then there is no reason for panic and we can return to our habitual life.